Actuator for power-operated adjustable beds



Feb. 13, 1951 MCVICKER 2,541,529

ACTUATOR FOR POWER OPERATED ADJUSTABLE BEDS Filed June 6, 1949 2Sheets-Sheet l @llllllll INVENTOR. GRAHAM 0. Mc VIC/(El? AGENT Feb, 13,1951 G. D. M VICKER 5 9 ACTUATQR FOR POWER OPERATED ADJUSTABLE BEDSFiled June 6, 1949 2 Sheets-Shet 2 Patented Feb. 13, 1951 UNITED- STATESPATENT OFFICE AG'EUATOR; FQB. POWERlf-QPERATED' ADJUSTABLE BEDS GrahamD.,McVicker, San.Diego, Calif;

Applicatiomlune-(i, 1949;,Serial N0. 97;.464

5;Ql"aims., 1

My invention relates; to an actuator for: power operated adjustable bed,more-particularly to: an improvement over my former patentapplications,Serial No. 632,692,, filed December 4,. 1.945., and Serial No. 17,304,filed. March 26 .1948, and, the objects? of my invention. are:

First, to provide an: actuator for power: operated, adjustable bed ofthis class, having novel jack. extension limiting'means, wherein themajor diameter of the jack screw threads; at opposite ends thereof istapered longitudinal-lyof the axis of: the screw, and the,corresponding, jack. nut. is internally tapered-1 inconforming,relationship therewith, permitting, the nut, to run out on: thescrewand.maintain. considerable longitudinal bearing for the-support of bedmechanismby: the jack when the helical; threads are substantiallydisengaged;

Second, to provide an: actuator for-power operated' adjustablebed:having. a helical jack screw, the opposite ends of which the majordiameter thereof is tapered longitudinally of the: axis of the screw;permitting the tapered portion. of the major; diameter of. the threads.to engage an internally taperedinternally screw threaded bore portion;in either endof. the nut, corresponding thereto, permitting. the nut.to, sustain. considerable load longitudinally of; the; screwwhen: thethreads of the nut and'screware disengaged, and providing for positivehelical engagement and meshing of: the nut and: the screw when turned ina direction tending: to cause engagement of the nut. and screw;

Third; to provide an actuator for peter operated: adjustable bedof thisclass, having jack screwmovement. limiting means, which substan;- tiallyeliminates the necessity for: complicated electrical limit switchcircuits for controlling the limitsof movement: of the mechanical:vjack: of said power operated: adjustable, bed adapted} to elevateand'lowercertain: portions of the; bed:

Fourth, to provide an. actuator for, power oper ated. adjustable bed;of: this class" haying iacl; means: in conncctiorrtherewith whichprovides an audible si nal when the jack: has: reached its travel limit.in either, direction;

Fifth, to provide.- a jaw; screw and nut which automatically provides.for-certain reciprocal amplitudeof jack screw. operation in eitherdirection longitudinally of, the axis. of the screw;

Sixth, to provide a jack screw and nut: having correspondingdiametrical. taper and" acompression. spring for maintaining the nut,at. its one diametrically tapered portionin.engagementwith theexternally diametrically tapered portion of slotted actuator memberadapted to. permitv certaint travel of the. actuator member over anactuator pin, permitting, the electric. motor in con neotion with theactuator to gainnormal speed without load; preliminary to theapplication of the full working load thereto; and

Eighth, toprovidean actuator, for power operated, adjustable bed. ofthis, class which is. very simple and economicalof; construction,efficient in, operation, and which will, not readily deteriorateror get,outlot order...

With these and other objects in, view, as will appear hereinafter; myinvention. consists of certain novelfeatures of. construction,combination andarrangement of parts andportions, aswillbe hereinafterdescribed in detail and particularly set forth: in the appended claims,reference being had. to the accompanying drawings and to the charactersofreference, thereon, forming a part of this; application, in which:

Fig, 1 is a fragmentary sidelelevational, View of my actuator forpoweroperated. adjustable bed, showing parts and, portions in. section toamplify the illustration; Fig. 2 isan enlarged, fragmentarysectionalview, taken fromthe line 27-2 of Fig, 1; Fig. 3.-is.afragmentary sectional view, taken from the line 3-3 of Fig. 2;, Fig. iis; anenlargedfragmentary sectional,view,,takenfrom the line d eofaF-ig: 1; and Fig. 5, is a fragmentary side elevational view of the,manualoperating handle. or my actuator for power operated; adjustable,bed, showing the same, in: thepower actuator casing, illustratedfragmentarily and in. section.

Similar characters of reference refer to similar parts and portionsthroughout. the several views of. the drawings.

The motor I-, gear. 2,. Pinion 3', shaftfl, bearings firandi 6,,casingcapLsprings 8, and. 9, jack screw it; nut H, actuator member, 12,actuator. pin 53, crank. it, crank bearing {5, bearing support. t6, pin;Id and the collars I8 and. It constitute the principalparts andportions. of. my: actuator for power operated adjustablelbed.

The-motor !-,.gea1'- 2,.pinion,3.,.shaft 4,. bearings 5 and 6., casingcap. 1, and thespring. 8,. are-all con..-

to, Serial. No. 17,304, filed. March 26, 1.94.8...

The, jack screw lliisprovided withanexternally helically screw-threadedportion Illa, at opposite ends of which straight shaft portions I b andH30 are integral, and which substantially conform to the minor diameterof the external screw threads Illa, with slight tolerance, so that theshaft portions I00 and "lb will slidably pass through the minor diameterof the internal threads I Ia of the nut II, which is fixed internally ofthe tubular actuator member I2. The major diameter of the screw threadedportion Illa of the jack screw IE! tapers toward each opposite end ofthe externally threaded portion Illa, as shown in Fig. 1 of thedrawings, and the internally screw threaded bore portion of the nut IIhaving the threads Ila therein is tapered from the minor diameter of thethreads Ila to the major diameter thereof, outwardly toward each openendof the bore portion of said nut II. It will be noted that theinternally tapered bore portion, at opposite ends of the nut II,substantially coincide in angular taper to the externally tapered majordiameter of opposite ends of the externally screw threaded portion IOaof the jack screw I0.

It will be noted that the actuator member I2 is provided with a bushingI2a therein, slidably fitted over an enlarged shaft portion Illd of thejack screw I0, for engagement with the spring 9, which is abutted to thebolt 9a, which extends through the end of the shaft 4 and thetelescopically mounted end We of the jack screw II]. The actuator memberI2 is provided with a longitudinally slotted portion I2b in its sidewall, near one end, engageable with the pin I3, which is an actuator pinsecured to movable structure of a conventional adjustable hospital bed,or the like.

As shown in Fig. 5 of the drawings, I have provided certain improvementsin the manually operated handle structure, wherein the handle I4 isprovided with a pair of collars I8 and I9, fixed thereon in spacedrelationship with each other, whereby the collar I8 engages the bearingI5 and the collar I9 maintains the bearing support I6 in adjacentrelationship with the bearing I5. This bearing support I6 is acup-shaped support, having internal screw threads IBa, engageable withexternal screw threads Ia of the casing cap I, and this bearing supportI6 replaces the casing cap bore cover 1b, all asshown best in Figs. 1and 5 of the drawings. The handle I4 is provided with a pin I1,extending therethrough, which is placed in spaced relationship to thefrusto-conical end portion I40. of the handle I4, which is insertableinto engagement with the bolt 2a connected to the gear 2.

The hollow shaft 4, as shown in Fig. 1 of the drawings, is improved bythe provision of notch portions 4a in the end thereof for receiving theopposed projecting ends of the pin I1, disclosed in Fig. 5 of thedrawings.

The operation of my actuator for power operated adjustable bed issubstantially as follows:

When the motor I is operated in the conventional manner by electricalswitches controlled by the patient or the nurse in charge of a patient,the jack screw I0 is operated until the nut II completely traverses thesame and reaches the end thereof, which correspondingly extends theactuator member I2 and elevates or lowers a portion of the adjustablebed to which the actuator is connected. It will be noted that when themotor I is started, the slot I2b provides free play of the actuatormember I2 before it engages the pin I3 in either direction, so that themotor I may attain a certain speed before fully engaging the load,whereby the requirement for high starting torque of the motor issubstantially reduced. After the motor has started the load, ashereinbefore described, by forcing the nut II into disengagedrelationship with one end of the screw threaded portion Illa of the jackscrew ID, the conforming tapered portions of the nut II and one end ofthe jack screw threaded portion Illa provides for the support ofconsiderable load by the screw I0 in engagement with the nut I I.

It is to be noted that the internally tapered screw threaded boreportion at each end of the nut I I provides positive seat for onediametrically tapered end of the externally screw threaded portion ofthe jack screw I0, and that continued rotation of the jack screw I0causes the threaded portions to cause a slight clicking sound, whichprovides an audible warning to the operator that the jack is fullyextended. Wear of the tapered portion of the screw threaded portionIlla, and its corresponding internally tapered portion of the nut I I,does not in any way affect the meshing relationship of the correspondingthreads of the nut I I and the screw I0, due to the fact that the weartakes place on the diametrically tapered portions thereof and does notaffect the approach to the lead of the screw and its correspondingthread internally of the nut II.

When the nut II, together with the actuator member I2, have beenretracted toward the motor I, causing the bushing I2a. to engage thespring 9, certain tension of the spring 9 maintains constant engagementof the nut II with the screw I0, so that operation in the extendingdirection of the actuator member I2 is automatic and without lag ordelay. When the actuator member I2 is fully extended from the motor I,it is normally under load, and therefore the nut II is maintained inpositive engagement with the threads Illa of the jack screw I0, wherebythe threads readily helically engage when the motor is reversed forretracting the actuator member I2.

When the source of electrical energy to the motor I fails, the cover11), as shown in Fig. l of the drawings, is removed, and the bearingsupport I6 is placed in screw threaded relationship with the casing capI, as shown in Fig. 5 of the drawings, which causes insertion of thefrustoconical ends Ida of the crank I4, into the bore portion of theshaft 4, and into engagement with the bolt 2a, which causes reciprocalmovement of the gear 2 longitudinally of the shaft 4 and laterally ofthe shaft of the motor I, which disengages the gear 2 from the pinion 3.When the handle I4 is fully inserted, the ends of the pin I! engage thenotch portions 4a of the shaft 4, and the collars I8 and I5 maintainlongitudinal disposition of the crank I 4 with respect to the shaft 4,while the bearing I5 provides for freedom of action in rotating thecrank I4 for actuating the jack screw I0 relative to the nut II.

It will be here noted that another important function of the slottedportion I2b of the actuator member I2 is to permit the travel of theactuator member I2 a certain distance longitudinally of the screw I0, sothat thread bearing may be gained within the nut I I, permitting thesubstantial engagement of thescrew It with the nut II before theactuator member I2 contacts the pin I3 and begins to exert force uponthe load or weight of the bed structure in connection with the pin I3.

Though I have shown and described a particular construction, combinationand arrangement of parts and portions, I do not wish to be limited 1; tothis particular construction, combination and arrangement, but desire toinclude in the scope of my invention the construction, combination andarrangement substantially as set forth in the appended claims.

Having thus described my invention, what I claim as new and desire tosecure by Letters Patent is:

1. In an actuator for power operated adjustable bed, a motor, gear meansin connection with said motor, a rotatably mounted shaft in connectionwith said gear means, a jack screw having an externally screw threadedportion diametrically tapered in converging relationship toward itsopposite ends, means connecting said jack screw to said shaft forrotation of the former by the latter, an actuator member having aninternally screw threaded nut cooperating with said diametricallytapered screw threaded portion for moving said actuator memberlongitudinally a predetermined amount, said nut conforming to saidexternally screw threaded portion of said jack screw, having outwardlydiverging portions at opposite ends thereof, substantially conforming tothe external diametrical taper at opposite ends of said screw threadedportion of said jack screw whereby said nut automatically stops movementlongitudinally of said screw when moved a certain distance in onedirection.

2. In an actuator for power operated adjustable bed, a motor, gear meansin connection with said motor, a rotatably mounted shaft in connectionwith said gear means, a jack screw having an externally screw threadedportion diametrically tapered in converging relationship toward itsopposite ends, means connecting said jack screw to said shaft forrotation of the former by the latter, an actuator member having aninternally screw threaded nut cooperating with said diametricallytapered screw threaded portion for moving said actuator memberlongitudinally a predetermined amount, said nut conforming to saidexternally screw threaded portion of said jack screw, having outwarddiverging portions at opposite ends thereof, substantially conforming Lto the external diametrical taper at opposite ends of said screwthreaded portion of said jack screw whereby said nut automatically stopsmovement ill longitudinally of said screw when moved a certain distancein one direction, a spring abutted longitudinally of said jack screw andengageable with said actuator member when moved in one directionrelative to the longitudinal axis of said jack screw and exerting itsbias for effecting ready engagement of the threads of the screw threadedportion and the nut.

3. In an actuator for power operated adjustable bed, a motor, gear meansin connection with said motor, a rotatably mounted shaft in connectionwith said gear means, a jack screw having an externally screw threadedportion diametrically tapered in converging relationship toward itsopposite ends, means connecting said jack screw to said shaft forrotation of the former by the latter, an actuator member having aninternally screw threaded nut cooperating with said diametricallytapered screw threaded portion for moving said actuator memberlongitudinally a predetermined amount, said nut conforming to saidexternally screw threaded portion of said jack screw, having outwardlydiverging portions at opposite ends thereof, substantially conforming tothe external diametrical taper at opposite ends of said screw threadedportion of said jack screw whereby said nut automatically stops movementlongitudinally of said screw when moved a certain distance in onedirection, a spring abutted longitudinally of said jack screw andengageable with said actuator member when moved in one directionrelative to the longitudinal axis of said jack screw and exerting itsbias for effecting ready engagement of the threads of the screw threadedportion and the nut, said actuator bar having a longitudinally slottedportion therein, and a pin, positioned in said slotted portion, adaptedto be connected with an adjustable portion of a conventional poweroperated adjustable bed.

4. In a power operated adjustable bed, a manual operating handle havinga frusto-conical end portion, a pin extending transversely therethroughin spaced relationship to said frustoconical end portion, a hollowshaft, in which said frusto-conical end portion is insertable, a gear onsaid hollow shaft having a pin in connection therewith, extendingthrough said hollow shaft, a slot in opposite side walls of said hollowshaft, through which said bolt extends, notches in said hollow shaft,engageable with the pins on said manual operating handle, saidfrusto-conical end portion of said handle engageable with said boltconnected to said gear.

5. In a power operated adjustable bed, a manual operating handle havinga frusto-conical end portion, a pin extending transversely therethrough,in spaced relationship to said frustoconical end portion, a hollowshaft, in which said frusto-conical end portion is insertable, a gear onsaid hollow shaft having a pin in connectiontherewith, extending throughsaid hollow shaft, aslot in opposite side walls of said hollow shaft,through which said bolt extends, notches in said hollow shaft,engageable with the pins on said manual operating handle, saidfrusto-conical end portion of said handle engageable with said boltconnected to said gear, a pair of collars on said handle, spaced fromsaid pin, a bearing support adjacent one of said collars, a bearinginsaid bearing support, engaged by the other of said collars, and meansengageable by said bearing support for holding said manual operatinghandle in certain position relative to said hollow shaft.

GRAHAM D. MCVICKER.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,416,182 Farmer May 16, 19221,858,624 Hess et al May 17, 1932 2,349,332 Angell May 23, 1944 FOREIGNPATENTS Number Country Date 10,396 Great Britain Aug. 13, 1886 12,524Great Britain Oct. 2, 1886

